Ball-mill



E. H. SCHMIDT.

BALL MILL.

APPLICATION FILED MAY 9, 1919.

1,351,793. PatentedSept. 7, 1920.'

' ATTORNEYS.

EDWIN H. SCHMIDT, jorinsrrnarron, linrzoim.

BALL-MILL.

To all whom it may concern:

Be it known that I, EDWIN H.-SOHMIDT, :1

Arizona, have invented certain new'and useful Improvements in Ball Mills; and I do hereby declare the following'to be a full,

clear, and exact description of the invention,

such as will ena ble others skilled in the, art to which it appertains to make andusethe same. i Y

This invention relates to ball-mills and particularly to an arrangement by which 'wear on the liners of such mills may be detected before it has progressed to such a degree that thefre is danger of the mill becomm damaged.

l3all-m1lls o1 usual construction comprise a rotary shell provided upon its inner face with liners formed of hardened steel, against which the balls and the material being ground impinge as the shell rotates; .Under the continual wear to which these liners are subjected during the operationof the mill,

they will in time be reducedto such thinness that they will breakthrough and me It be quicklyworn through, and the'mill may be seriously damaged. The liners are not conveniently accessible for inspection, and it is necessary to shut down'the mill, and even remove some of its parts in order to .permit examinationof the liners. This.

causes a loss of time'in the operation of the 'mill, and a consequent decre'asein its efli ciency. So many factors enter into the question of the life of the liners that it is diflicult to predict beforehand how long any particular liner will last. The efliciency of I the mill will be still further reduced if it has to be stopped for frequent inspection, as i 1 different liners will be subjectfto different amounts ofwear according to their location in the mill, and one must keep watch upon all of the liners in order to insure that worn ones may be replaced before damage occurs.

It is an object of this invention to over come thesedisadvantages of ball-mills of the usual construction by provlding an arv rangement by which the worn condition of i the liners may be detected without the necessity of stoppingthe mill and making an may be easily applied to existing mills with- Specification of Letters Patent. pat fi s mlq; 920 Application fiIedCLVIay 9, r r Y 1919. Serial Nb. 295,933.

provided in connection with each linerisectlon, tin-arrangement whereby some of the contents of the mill will: be permitted "to In accordance with the inventionthere out any substantial changes in their' struc ture. citizen of the United States, residing at In spiration, in the county of Gila, State of escape if the corresponding liner sectionjb'ecomes worn to such an extent that it should. be replaced, thus giving an indication of-the condltlon of the liners that may be observed even while the mill isin operation. The in .ventlon may be embodled 1n varlous forms,

some'of which are shown in the accompanylng drawings, in vwhlch,

l 7' hignre 1 1s a sectional vlew through the icentral portion of the shell of a mill showing the liners in'place with-one'form of the 5 invention applied thereto;

1* 1g. 2 1s an enlarged sectional'vlew of one with the arrangementof F 1;

ofthe indicating or sentinel-bolts employed 7 i Fig. 3 is a sectional view of a liner with a 1 pipe instead of a bolt;

Fig. 4 1s a simllar. view showing another form of bolt that may be used;,and

Fig. 5is a similar view showing the indieating device formedf'as a part of the liner;

projecting through the shell. V Y i The ball-milhwhich maybe of any prein detail herein, comprises a'shell 10 upon 8 5 terred construction,-and whichis not shown the interior of which are liners 1l formed of 7 suitable hardened steel and" retained in place by bolts 12hav1ng their heads countersunk in the thickerportions of the. liners. The;

liners are shown ofa shape particularly well adapted to coiiperate with the balls of the 'i In'ill infproducing' a grinding. effect; but it will be understood that the liners maybe oi.

any other shape, and that the invention is equally applicable to all-liners.-

In accordance with theembodiment of the V invention shown in Fig.1, there is associated with each liner section one or more indicating or sentinel-bolts 13, preferably having their heads countersunk within the liner at the point where maximum wear occurs. These. sentinel bolts will usually be applied to the. liner sections at points midway between their endsjor, in other words, at the central zone ofthemill. Each of the bolts .is provided with a'bo're or socket 14 extending part way into the head 15, and the bolts The arare threaded to permit retaining nuts l6rto be screwed thereon. The bolts are countersunk 'within the liners so' that. asthe liners sentinelbolts may 7 maybe screwed into wear away, come exposed and ultimately worn away with the liners, thus placing the lboreshin communication with the interioriof the mill,

and allowing water and pulp to seep or leak through the bolts to give an indication of the worn condition of the liners, whereupon the mill may be stopped for repairs. The

shapes according to the particular liners with which they are to be used.

1 Instead of bolts, short pieces of pipe 17 sockets 18 in the liners,

as shown in Fig. 3. These pipes project through the shell of the mill. and may be such as shown in Fi 4 ma clamped inplace by nuts l9. flVith this arrangement when the liner, wears away sothat. the

place by a nut2l. The headof the bolt will as the liner wears the shank of giving ultimately be worn away down, and when this occurs the bolt Wlll drop out, this, in itself,

an indication of the worn condition of the liner, but, in addition some of. the material. within the mill will'be discharged 4 through the aperture thus produced, and will in arrangements that do not require the use give a further indication of the worn condition of the liner. It will be noted that the liners are held in place by two bolts, the heads of which may be so proportioned and which may be set different distanceswithin the liners so that one head will wear oil before the other one does, whereupon the one worn or allow material away will either drop out to escape through its bore, while theliner'is still securely held in place by the other belt. Obviously it would bea disadvantage to have the liner held in place by but a single bolt, subject of the large piece of; metal withinthe shell. which would tend to damage it.

. In addition to the modifications described above the invention mayalso be embodied of separate members, such belts or pipes.

' One such arrangement is shown in 5 wherein the liner is provided with one or more knobs or projections 22 extending from its outer face opposite the zone of maxiwear. 4 These projections -'6Xl36I1Cl through the shell, and suitable gaskets 23 the heads of the bolts will be- I be formed of either hard or soft metal, and of different sizes and when thelliners wear away combination of hollow through the shell and having their inner to wear, which, when worn. away, wouldfrelease the liner entirely from I the shell thus exposing thatpart shellrto wear, and also'releasing an unduly leading from outside saidmay be used for preventing any leakage around the pro ections. provided with av bore or socket 24 which extends into the body of the linera sutficient distance so that when the liner becomes worn to a dangerous point the' bore will be opened to permit the leakage of material from the mill to ive anindication.

The modifications scribedabove are some of those'in which the invention may be embodied, but it will be understood that it may, also be'embodied Each projection is illustrated and de- 7 in. other forms, and that various changes in the detailso'f constructlon of the particular A arrangements illustrated may be made without departing from the principle of the invention as defined in the appended claims.

I claim: I I 1; In a ball mill, a shell, liners mounted on the inside of said shell, and a sentinel device provided with a bore associated with said shell, which, when wornaway a certain amount, allows material to escape from V the inside of said shell to the outside thereof. 7 p i ,2. A. ball-mill comprising a shell, liners secured upon the inside oi the shell, and hollow members associated with the liners and extending into the same a suilicient distance to permit their bores to be exposed to a predetermined degree.

3. In a ball-millprovided with a shell I having liners secured upon its inside, the

members pro ecting ends, within the liners so that when the liners wear away the bores of the members wlllbe placed '111 communication with the "interior of the shell to permit leak age of thecontents of. the mill to give an indication of the worn condition ofthe liners.

V 4:. Ina ball-mill. provided with a shell having. liners secured upon its inside, ,the combination of bolts having their heads countersunk in the liners at the zone oi maximum wear andtheir shanks projecting bolts being formed witha-socket extending into the portion'o't the boltthatlies within the liner so that as the liners wear away the sockets will be placed in communication with the interior of the shell to permit leak age of the contents of the mill to give an indication of the worn ,condition of the liners.

5. A ball mill, comprising a shell, aliner within said shell and means adapted to secure said liner to said shell, having abore shell .to within said lining. H p I i In'testimony whereof I aflix my signature.

EDWIN soiiMin'T.

, through the wall. of the shell, each of said 

